Electrolytic apparatus



W. E. GREENAWALT. ELECTROLYTIC APPARATUS. APPLICATION FILED JUNE I3, I914. RENEWED APR. 5. 1919.

1,365,034. Patented .1111. 11,1921.

FIG 2 EN 223135 4 INVENTOR WILLIAM E. GREENAWALT, 0F DENVER, COLORADO.

ELECTROLYTIG APPARATUS.

Application filed June 13, 1914, Serial No. 845,011.. Renewed April 5, 1919, Serial No. 287,925.

To all whom it may concern:

Be it known that I, WILLIAM E. GREENA- wanna citizen of the United States, residingin the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Electrolytic Apparatus, of which the following is a specification.

The invention has for its more immediate objectflthennaiutaining of the variable valent salts in an impure electrolyte at their lowest valency, and thus,- toa large extent, increase the cathode efliciency.

The apparatus will be described more particularly as applied to the electrolysis of impure copper sulfate solutions, as for 8X-.

ample, those obtained in leachin copper ores, although it is not intended to limit it to this use. ther applications will suggest themselves to those skilled in the art.

In the electrolysis of impure copper sulfate solutions, as for example those obtained in leaching copper ores, there is always present iron sulfate, which injuriously affects the operation. Ferrous sulfate in the electrolyte is not particularly harmful, but the ferric sulfate is highly detrimental.

llf a solution of copper sulfate, containing ferrous sulfate, is electrolyzed, copper is deposited at the cathode while sulfuric acid and "ferric sulfate are produced at the anode, as represented by the following equations 'lhe ferric sulfate, finding its way back to the cathode, combines with the deposited copper and is again reduced to the ferrous condition, thus representing a loss of (Billciency, as represented by the equation:

lf, however, the ferric sulfate can be reduced at the expense of a comparatively cheap reducing agent, such as hydrogen sulfid or sulfur dioirid, then acid is re generated,and the iron in the electrolyte loses its ability to combine with the deposit-- ed copper, as shown by the equation:

So that for every molecule of iron that is reduced from the ferric to the ferrous condition, one molecule of acid is regenerated and an atom of sulfur liberated. The

acid is beneficial in the electrolyte, and on leaving the electrolyzer, is further available process application, Serial No. 812,951, filed January 19, 1914. This application may be regarded as directed to the apparatus corresponding with the above process applications.

Hydrogen sulfid, while a most effective reducing agent, is also an effective precipitent of copper from acid solutions, hence it has to be applied with care in order to get the desired reduction of the variable valent elements while at the same time avoiding the precipitation cf any perceptible amounts of copper as the sultid.

if hydrogen sulfid is applied to a copper solution containing ferric salts, the forric iron is reduced to the. ferrous condition before the copper is precipitated, jas-shown by equation l. Manifestly, therefore, the

hydrogen sulfid is preferably applied in such amounts and in such state of dilut1on that the variable valent salts will be reduced without perceptably precipitating the copper. A small amount of the gas should be applied to a relatively large amount of the electrolyte. if, however, a small amount of the copper is precipitated chemically, as the sulfid, no harm will result; in fact it may be beneficial, as the cupric sulfid will also have a tendency to reduce the variable valent salts, as shown by the reaction:

5. CuS-l-l e (S0,),:CuS,{-2Fe$@,l-S.

the next, and Fig. 2 a modified arrangement in which the gas is introduced into the elec trolyzer direct.

kipecification of Letters Patent. Patented Jim, 1 9 1921.

ill:

lit?

In the figures, 1 represents a tank containing the electrolyte, which may be presumed to be copper sulfate solution as'obtained from leaching copper ores, and necessarily containing soluble salts of iron. 2 are the anodes, and 3 the cathodes. 4 is a frame, having stirring bars 5, interposed between the electrodes, if it is desired to stir the electrolyte; This frame reciprocates, as a whole, and is suspended from the track 6 by the rollers 8 and is moved by the mechanism 7.

10 represents a mechanism. taken as a whole, by means of which the gas, say hydrogen sulfid, is brought into a minute state of subdivision, or atomized, in contact with the electrolyte, and consists, preferably, of a tube, hood, or cylinder 11, having perforations 12, in its periphery, or in disks 12, suspended in the solution, or electrolyte, by the shaft 13, from the ball bearings 14. This cylinder or hood is made to revolve at a high speed, driven by the motor 16. The gas is preferably produced in the hydrogen sulfid generator 17, from iron sulfid and dilute sulfuric acid, and, by means of the compressor 18, is forced, with the air, through the pipe 19, and into the atomizer 10, and into the revolving cylinder 11 through the stationary nozzle 19 It is desirable to maintain a circulation of the electrolyte. It may also be desirable to agitate the electrolyte. The idea is to bring a large volume of solution in contact -with the gas for the reductionof the variable valent salts, and then bring a large volume of the reduced solution in contact with the electrodes, and to prevent,.as far as possible,

the variable valent elements from being oxidized to the higher valencies. This agitation and circulation is effectively accomplished' by forcing the gas, preferably from a stationary pipe 19, into an inverted perforated cylinder or hood, while the cylinder is in rapid rotation. The gas, escaping from the nozzle 19, is trapped by the hood or cylinder, and as the pressure accumu- 'lates, it forces its way out of the perforations 12. As the cylinder and perforations are revolving at a high speed, the gas is distributed in exceedingly small subdivisions, or atomized, in contact with the solution. By regulating the speed of rotation, the amount and dilution of the gas, and the volume of electrolyte, the variable valent salts may be readily reduced and maintained reduced without chemically precipi tating an appreciable amount of the copper as the sulfid, with the hydrogen sulfid.

The air and gas ascending't'hrough the apparatus 10, acts as an air lift and raises the level of the solution in the atomizer above the level in the electrolyte tank from whichit is flowing, and permits of its being introduced into the next tank, which may be on the same level as the first. If, therefore, there are a number of tanks in series, it is desirable to flow the solution from the first to the second by passing it through the atomizer 10, and so on through the entire series, as shown in Fig. 1. Under these conditions the amount of ferric salts formed will be quite small, due to the general circulation of the electrolyte, and partially due also, if desired, to the small amount of copper sulfid formed by the hydrogen sulfid, and which, due largely to its extremely fine state of division in the electrolyte, will also act as an effective reducing agent to maintain the iron in the ferrous condition. If

,thus prevent the migration of any ferric ions from the anodes to the cathodes.

The space in the upper portion of the atomizer 10, is inclosed, as shown by 28, so as to collect the excess gas and air, which may then be exhausted into the atmosphere outside of the building, but it is preferably returned to the gas generator 17, through the pipes 22, and again enriched in the gaseous reagent, thus avoiding any Waste of gas, while at the same time it is prevented from becoming a nuisance, as it would be if allowed to escape indiscriminately. However, if hydrogen sulfid, for example, is used .as the reducing agent, no excess of gas is likely to escape from the electrolyte, because it is such an energetic reagent, that the small amount which might be in excess of that required to reduce the variable precipitating copper as sulfid. If sulfur dioxid, for example, is used as the reducing agent, some of the gas is quite-likely to escape from the electrolyte, in which case it might with advantage be returned to the compressor and gas 1 generator for restrengthening, or forced from one cell to the next until all the gas is consumed. If desired the electrolyte may be filtered, as shown at 30, to remove precipitated sulfur, sulfid, or other insoluble impurities.

The process and apparatus has been more particularly described in reference to the electrolysis of copper sulfate solutions, using hydrogen sulfid or sulfur dioxid as the redu'cing agent. Other gases may be used as reducing agents. It is applicable to chlorid solutions. Manifestly, also, the same apparatus may be used to apply an oxidizing gas to the electrolyte, if it is desired to raise the valency of the variable valent elements instead of reducing the valency. The

method of procedure would be much the (till lib means-rand copper sulfid is precipitated, it will be in a fine state of division and the agitation and circulation of the electrolyte will tend to keep the copper sulfid in suspension, and

thus assist in maintaining the iron in the ferrous condition, as set forth by equation 5.

The apparatus embodied in this invention, in which the gas atomizer is submerged in the electrolyte, presents marked advantages over the usual scrubbing tower for this purpose, and over spray nozzles, which require pressure of the liquid to make them effective. The handling of corrosive solutions, especially under pressure, as required by spray nozzles, is diiiicult of practical accomplishment and the delicate regulation of the gas and liquid is quite impossible. ln my apparatus, as preferably constructed, the gas atomizer issubmerged in the liquid and the gas introduced into the rapidly revolving atomizer without any direct mechanical connection, hence the atomizer may be simply constructed of lead, or any other suitable material, without annoying pipe connections for the gas. The submer ed orifice 19 for the gas is preferably located in the bottom of the tank or receptacle for the electrolyte and the mechanical connections made on the outside.

I claim:

1.. ln electrolytic apparatus, an electrolyzer, means for agitating the electrolyte, means for segregating a portion or the electrolyte out of contact with the electrodes, means for introducing a gaseous reagent into the segregated portion of the electrolyte through a submerged opening, rotating means submerged in the electrolyte tor finely subdividing the gaseous reagent in contact with the electrolyte, and means for return ing the electrolyte treated with the gaseous reagent to the electrodes.

2. ln electrolytic apparatus, a tank adapted'to contain the electrolyte, an agitatorhaving perforations submerged in the electrolyte, means for rapidly rotating the agitator, means tor delivering a gaseous reagent from a stationary orifice to the agitater and passing it through the perforations and thus atomizingthe gas in contact with the electrolyte, and means for passing an electric current through the electrolyte treated with the gas.

3. ln electrolytic apparatus a chamber separate from the electrolyzer, means for agitating the electrolyte in said. chamber and means for maintaining a finely divided sulfid reagent in suspension in the electrolyte in said chamber, means for separating the soluble from the insoluble matter in the electrolyte, and means for returning the electrolyte to the electrolyzer.

l. ln electrolytic apparatus means for introducing into the electrolyte a sultid reagent, means for atomizing the sulfid reagent in contact with the electrolyte, means for maintaining a sulfid reagent in contact with the electrolyte, and means for separating the insoluble from the soluble matter in the electrolyte and means for returningJ-he electrolyte to the electrolyzer.

5; In electrolytic apparatus a tank containing the electrolyte and electrodes, means for segregating a portion of the electrolyte out of contact with the electrodes, an agitator suspended within the electrolyte, means for forcing a gaseous reagent into the segregated portion of the electrolyte, means for rotating the agitator with sufficient rapidity to atomize the gas in contact with the electrolyte, and means for circulating the electrolyte by alternately withdrawing it from the electrodes and returning it to the electrodes.

6. ln electrolytic apparatus a tank containing the electrolyte and electrodes, means for segregating a portion of the electrolyte out of contact with the electrodes, an agitator having gas passages suspended within the electrolyte, means for forcing a gaseous reagent into the segregated portion of the electrolyte, means for moving the a itator with sutlicient' rapidity to atomize the gas in contact with the electrolyte, and means for circulating the electrolyte by alternately withdrawing it from the electrodes and returning it to the electrodes.

7. ln electrolytic apparatus means for. lowing the electrolyte from one cell to the next in a continuous stream, an agitator submerged in the stream of electrolyte, means tor applying to the stream of electrolyte a gaseous reagent, and means for rotating the agitator with suflicient rapid 'ity to atomize the gas in contact with the stream of electrolyte.

8. ln electrolytic apparatus, an electrolyzer, a gassing chamber communicating with the electrolyzer and adapted to contain a liquid and to confine a gas over the liquid and having a inlet and a gas outlet and a liquid inlet and. a liquid outlet, a rotary gas impregnator having gas passages extending from its interior toward its exterior suspended within the gassing chamber and submerged in the liquid, means for rotating the impregnator about its vertical axis, means for causing a flew of gas through the gas passages of the rotary impregnator from the interior toward the exterior and into the liquid and atomizing the gas in the liquid, and means for causing a flow of gassed liquid from the gassing chamber to the electrolyzer and electrolyzed liquid from the electrolyzerto the gassing chamber.

9. ln electrolytic apparatus, an electrolyzer, means. for applying hydrogen sullid to the electrolyte, means for atomizing the hydrogen sultid in contact with the electrolyte, means for maintaining a ran sulfid reducing agent in contact with the electrolyte, and means for electrolyzing the resulting reduced electrolyte.

10. In electrolytic apparatus, an electrolyzer, means for applying a gaseous reagent to the electrolyte, and rapidly moving means for atomizing the gaseous reagent in contact with the electrolyte.

11. In' electrolytic apparatus and in connection therewith, an electrolyzer, a cylinder containing a portion of the electrolyte, an agitator suspended in the electrolyte and within the cylinder, means for introducing a gaseous reagent into the electrolyte in the cylinder, and means for rotating the agitator with sufficient rapidity in the path of the ascending gas to atomize the gas in contact with the electrolyte.

12. In electrolytic apparatus means for introducing a finely divided sulfid reducing agent into the electrolyte, means for agitating the finely divided sulfid reagent in contact with the electrolyte, and means for preventing the finely divided sulfid reagent 'from coming in contact with the cathode.

13. In electrolytic apparatus a tank adapted to contain the electrolyte, means for in troducing a gas into the tank and into the electrolyte from a submerged opening having no mechanical connection with the moving mechanism Within the tank for atomlzing the gas, and moving means having gas passages for atomizing the gas in its ascent through the electrolyte submerged in the electrolyte, and means for-electrolyzing the gassed electrolyte.

14. In electrolytic apparatus, an electrolyzer, a gassing chamber communicating with the electrolyzer and adapted to con tain a liquid and to confine a gas over the liquid and having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet, means for introducing a gas into the gassing chamber, means for continuously treating the liquid in the gassing chamber with the gas, means for causing a flow of gas,

through the gassing chamber, and means for -causing a flow of electrolyzed liquid from the electrodes to the gassing chamber and of gased liquid from the gasing chamber to the electrodes.

15. In electrolytic apparatus, a tank adapted to contain the electrolyte, an atomizer having a multiplicity of gas passages arranged at-variable distances from a central axis suspended within the tank and submerged in the liquid, means arranged for introducing a gas into the tank and by the pressure of the liquid'in the tank forcing it through the, gas passages in the atomizer, means for rotating the atomizer, and means for electrolyzing the liquid.

16. In electrolytic apparatus, a tank adapted to contain the electrolyte, an atomizer having gas passages extending from introducing a gas into the electrolyte in the gassing chamber so as to rise through the electrolyte by thepressure of the liquid on the gas, means for subdividing the gas in its ascent through the electrolyte and causing a difference in the level of the liquid between the electrolyte tank and the gassing chamber and means for causing a flow of electrolyte from the electrodes to the gassing .chamber and from the gassing chamber to the electrodes.

18. In electrolytic apparatus, a tank adapted to contain the electrolyte and the electrodes, a gassing chamber communicating with the electrolyte tank, means for in troducing a gas into the electrolyte in the gassing chamber so that it will rise through the electrolyte by the pressure of the liquid on the gas, means for subdividing the gas in its ascent through the electrolyte and causing a difference in the level of the liquid between the gassing chamber and the elec the gassing chamber to the electrolyte tankby the difference in the level of the liquid induced by the gas in the gassing chamber.

19. In electrolytic apparatus, a tank adapted to contain the electrolyte and the electrodes, a gassing chamber communicating with the electrolyte tank and adapted to confine a gas over the electrolyte, means for introducing a gas into the gassing chamber, rotary means forsubdividing the gas in the gassing chamber, means for causing a flow of gas through the gassingchamber', and means for causing a flow of electrolyte from the electrodes to the gassing chamber and from the gassingchamber to the electrodes.

20. In electrolytic apparatus, an electrolyzer, a gassing chamber having a gas inlet and a gas outlet and a liquid inlet. and'a liquid outlet and adapted to contain a liquid and to confine a gas over the liquid, means and the liquid, and means for causing a flow of liquid from the gassing chamber to the electrolyzer and from the electrolyzer the gassing chamber. v

21. In electrolytic apparatus, an electrolyze'r, a gassing chamber communicating with the electrolyzer and adapted to contain a liquid and to confine a gas over the liquid and having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet, means for introducing a gas into the gassing chamber, means for causing a flow of gas through the gassing chamber, means Within the chamber for intimately mixing the gas and the liquid, means for causing a flow of gassed liquid from the gassing chamber to the electrolyzer and from the electrolyzer to the gassing chamber, and means for electrolyzing the liquid.

22. In electrolytic apparatus, a tank adapted to contain a liquid, a rotary atomizer having gas passages extending from its interior toward its exterior suspended within the tank and submerged in the liquid, means for causing a flow of gas into the interior of the atomizer, means for causing a flow of liquid from the tank into the interior of the atomizer, means for causing a flow of gas and liquid from the interior of the atomizer toward its exterior and into the liquid in the tank, means for rotating the atomizer about its vertical axis, and means for electrolyzing the liquid.

WILLIAM E. GREENAVVALT.

Witnesses: I

EDWIN J. CHIssELL, THOMAS S. WALTEMEYER. 

